Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare this a safe, closed-world read, so the bar is low. The description adds genuinely non-obvious behavior: the call blocks for up to waitSeconds (capped at 25), so an agent knows to expect latency rather than an instant snapshot.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three tight sentences, front-loaded with what the tool does and how long it blocks. The final sentence describing the returned image URL and step colours partly duplicates the output schema, which is the only waste.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a two-parameter polling tool with a full output schema and read-only annotations, the essentials are covered: what it polls, the blocking cap, and what a completed result carries. It doesn't say what a timed-out or failed job returns to the agent, a minor gap given the output schema may cover it.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% and the schema already says jobId comes from confirm_look_generation and waitSeconds ranges 0-25. The description restates the 25 cap but adds no format, default, or trade-off detail beyond the schema. Baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Check a try-on') and anchors it to the originating sibling ('started by confirm_look_generation'), which separates it from try_look_from_photo and list_my_generations without opening any schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The 'started by confirm_look_generation' clause makes the correct sequencing explicit, and the wait semantics imply polling. It stops short of saying what to do on timeout or when to call again, and names no exclusion case.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.